Hot teacher reserving shady place for port official (13)

I believe the answer is:

harbourmaster

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'reserving shady place for port official' is the definition.
I don't know anything about this answer so I can't judge whether this works.

'hot teacher' is the wordplay.
'hot' becomes 'harbour' (I am not sure about this - if you are sure you should believe this answer much more).
'teacher' becomes 'master' (I've seen this before).
'harbour'+'master'='HARBOURMASTER'

Can you help me to learn more?

I've seen this clue in The Telegraph.

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